This invention relates to a catheter and, more particularly to a valve for use with a standard catheter, which minimizes back flow of fluid.
In modern medicine, a catheter has many uses. A catheter for intravenous use has a flexible tube of various lengths attached to a hub. A needle assembly cooperates with the catheter, in order for the flexible tube to be inserted into a patient. After the needle is removed, then appropriate medication or other desired material is inserted through the hub into the flexible tube and thence into the patient.
In operation, the catheter is inserted into a patient with the needle assembly. A needle of the needle assembly is inserted into a blood vessel of a person. The tube from the catheter is pushed down the needle, threaded therethrough, thereby inserting the tube and leaving the same in that blood vessel. Attached to the hub of the catheter may be a series of devices, which permit access to the tube. In this manner, a person may be given medicine, have blood samples drawn therefrom, or receive any other desirable medical procedure requiring fluid to be put in or taken out as desired.
Undesired fluid flow is a problem with the catheter. Many types of check valves are known for preventing such an undesired fluid flow. Typically, adding a check valve requires replacement of the entire catheter unit. Most hospitals are reluctant to take such action and do a complete replacement of familiar equipment. If a check valve can be developed and used with an existing catheter, great advantages are obtained.
Some of those check valves save an elastomeric nature, which causes a sealing of the valve and stoppage of the fluid flow as undesired pressure is put on the check valves. Unfortunately, these elastormeric valves are expensive. Furthermore, such valves need to be replaced often because they lack durability.
Sometimes an elastomeric valve is used with a concave seam surface. Such a valve must be a floating valve and smaller than the concave area. Such a structure permits debris to be trapped between the valve disc and the concave surface. Such debris, of course, interferes with the proper functioning of the catheter.
Another desired use of a catheter is to permit blood samples to be taken therethrough. However, a check valve can interfere with this procedure. Thus, the check valves of the prior art cause other problems, too.
A check valve must work in the catheter. Flow of fluid interference must be minimized. Also, there must be no interference with a desired fluid flow. Such required features are clearly contrary. Maximizing of one feature minimizes the ability to maximize the advantage of the other feature. Thus, a check valve which can maximize the advantages of both requirements provides a great advantage to the art.
Therefore, among the many objectives of this invention is to provide a valve, which is insertable into an existing catheter.
A further objective of this invention is to provide a check valve for a catheter.
A still further objective of this invention is to provide a valve for a catheter, which permits drawing of blood samples through the catheter.
Yet a further objective of this invention is to provide a valve for a catheter, which minimizes undesired pressure on the valve.
Also, an objective of this invention is to provide a durable check valve for a catheter.
Another objective of this invention is to provide a valve for a catheter, which minimizes undesired fluid flow.
Yet another objective of this invention is to provide a valve for a catheter having a simply designed structure.
Still, another objective of this invention is to provide a valve for a catheter being easily manufactured.
These and other objectives of the invention (which other objectives become clear by consideration of the specification, claims and drawings as a whole) are met by providing a valve insertable in a standard catheter, wherein the valve prevents undesired backflow of fluid and provides for blood samples to be taken through a standard catheter.